As General Motors prepares to launch its critical rebirth as a public company the papers it filed with federal regulators, this week, reveal last year’s bankruptcy didn’t solve all of the maker’s financial woes in its home market.

In the S1 form the maker filed with the U.S, Securities Exchange Commission, this week, GM disclosed its U.S. Hourly Pension Fund is underfunded by more than $17.1 billion. In addition, the company potentially could owe even more money to the Voluntary Employees Benefit Association, or VEBA, controlled by the United Auto Workers, GM said.

The company’s pension funds have historically been “well managed and even had surplus cash between 2005 and 2007,” it claimed in the filing for its planned IPO. But a host of factors, in the wake of the financial crisis in 2008 and 2009, have resulted in a decline in assets, according to the documents filed with the SEC.

GM cautioned that, “Our U.S. defined benefit pension plans are currently underfunded, and our pension funding obligations may increase significantly due to weak performance of financial markets and its effect on plan assets. The GM Pension plans, also have been hurt by the prevailing low interest rates.”

GM also owes another $10 billion to its non-U.S. pension fund, according to the S1.

Free Subscription!

The disclosures about the pension fund were included in the long list of potential problems the automaker listed inside the lengthy and complicated S1 to alert investors to the fact that shares in the new GM could be a risky investment.

Recession, a drop in the company’s cash flow or financial difficulties at key suppliers and partners also are serious threats, according to the documents.

Could GM clear the hurdles and emerge from bankruptcy as early as July 10?

General Motors officials are back in court this morning, and what they have to say could determine the future of the bankrupt automaker.

Just a month after the 101-year-old company entered Chapter 11 protection, it is on track for a swift re-emergence as a “new” GM, possibly as soon as July 10th. But before that can happen, the automaker needs to get court approval to shed debt and bad assets, selling its “good” assets to an all-new entity that will have the federal government, a union health care fund, and two Canadian government bodies as its dominant shareholders.

The first critical step in a so-called “363 Sale” began on Tuesday with a hearing in federal bankruptcy court, in New York City. The hearing is continuing today, and despite the strong support of the Obama White House, there will be plenty of objections raised to the plan GM has laid out – a proposal that would, among other things, leave thousands of dealers losing their franchises, and bondholders swallowing billions in debt.